What is keratoconus?
Keratoconus is a thinning of the front surface of the eye, the cornea. The cornea is normally round and clear, which helps focus the light that enters the eye. As the cornea thins, it can bulge into an irregular cone shape, causing progressive visual distortion and eventually severe vision loss. Keratoconus generally affects both eyes, but is usually asymmetric with one eye progressing more rapidly than the other.
What causes keratoconus?
The cause of keratoconus is still unknown, but appears to be multifactorial and maybe a common final pathway of different pathological processes. It has both genetic predisposition and suspected environmental factors that may cause the disease. Eye rubbing and allergic conditions have been implicated as causative factors. Keratoconus is more prevalent in patients with certain conditions, including hay fever, asthma, eczema, Down’s syndrome, mitral valve prolapse, and Marfan’s syndrome.
How common is keratoconus?
The prevalence keratoconus is approximately 1 in 2000 but can be significantly higher in certain populations. There does not appear to be any difference between males or females. Keratoconus may appear between the ages of 8 and 45, however, it is most often diagnosed in the teens through early thirties.
What are the symptoms of keratoconus?
The initial symptoms of keratoconus are usually blurry, distorted vision that may be amenable to correction with spectacles or contact lenses. Frequent changes to spectacle or contact lens prescriptions may be necessary if the cornea is becomes progressively thinner and bulges. Advanced keratoconus can lead to very poor vision that may not be corrected with spectacles or contact lenses, and may require a corneal transplant.
How is keratoconus diagnosed?
The diagnosis can be confirmed with a complete eye examination by an experienced ophthalmologist, who will look at your refraction, slit lamp examination, and measurements of the curvature of your cornea. Dr. MacIntyre is a very experienced cornea specialist who will closely examine your eyes and use the most modern corneal tomographers to accurately assess your corneal curvature and corneal thickness. He will explain his findings, accurately diagnose and determine the severity of your keratoconus, and answer all of your questions during the initial consultation.
Some studies have shown that between 20% and 50% of relatives of people with keratoconus have abnormal corneal measurements as determined by corneal tomography and as many as 8% may have advanced keratoconus. It is very important to have other family members screened for keratoconus, particularly if there has been any vision change or if they are younger in age.
What is the treatment for keratoconus?
The treatment of keratoconus can be divided into two parts: visual rehabilitation and prevention of progression of the disease.
1. The vision can be rehabilitated with spectacles or soft contact lenses early in the disease. As the disease progresses, rigid gas permeable contact lenses may be necessary. Historically, about 10 to 20% of cases progressed to a state where corneal transplantation was required.
2. Preventing the progression of the disease is now possible with the advent of Corneal Collagen Cross-linking.